On 7/24/15 7:13 PM, deadalnix wrote:
On Friday, 24 July 2015 at 19:56:55 UTC, Shammah Chancellor wrote:
I put up a PR for phobos awhile ago for concepts as a library to kind
of start the discussion around concepts. There seemed to be some
interest around the PR, so I have rebased it and fixed the formatting.
Please take a look:
https://github.com/D-Programming-Language/phobos/pull/2627
-Shammah
Doing it as a library would miss a lot of the point of concepts :
- Compiler can do a fair amount of semantic analysis on template
before instantiating them. This work is done once rather than repeating
it a every template instantiation.
Interesting.
- It allow for much more clearer error messages. Anyone having to
maintain some meta code will understand what I'm talking about here.
Agreed, though I would more if "much" were dropped.
- It make compile time and runtime polymorphism more alike. I do think
we'd all agree that Andrei approach to mention template arguments as
compile time arguments and go from there is a good move. Concept would
be the same move, but for typing. By reusing common language constructs
(C++ failed to use that opportunity) for instance.
Meh to that.
Now stack these advantages against the advantages of template
constraints. It's a landslide.
Andrei
